Four French soldiers are being questioned in an investigation into alleged child sexual abuse in Central African Republic, reports The Guardian.

The criminal inquiry into claims that French peacekeepers raped children and demanded sex for food was launched earlier this year, after The Guardian revealed that a senior UN official had been suspended for leaking details of the alleged abuse to the French government.

The interrogations on Tuesday appear to be the first time anyone has faced judicial questioning in the 19 months since the accusations were first made against French troops sent to protect CAR civilians displaced by sectarian violence.

The disturbing case has raised questions about how international peacekeeping forces handle suspected abuses by their soldiers.

One of the four soldiers had been formally detained and the others were still being interrogated as suspects, the spokeswoman for the Paris prosecutor’s office, Agnes Thibault-Lecuivre, told Associated Press. No one has so far been charged in the case, which is being handled by Paris magistrates.

Fourteen people are reportedly under investigation. None of the four soldiers being questioned on Tuesday have been publicly identified and it is unclear what they are suspected of.

In May and June 2014, several boys described sexual abuse by French troops to UN investigators in CAR capital Bangui. The French defence ministry said it was informed in July 2014 of the accusations, and French prosecutors opened a preliminary investigation.

But the accusations were not made public until the Guardian’s revelations in April this year. The French government has not explained why the investigation was kept quiet, although the French president, François Hollande, has promised tough punishment for any soldier found guilty.

The alleged abuse took place as French peacekeeping troops were supposed to be protecting civilians at a centre for displaced people near the airport in Bangui, between December 2013 - when the French military operation began - and June 2014.

Residents of a refugee camp outside the capital said the soldiers had targeted boys as young as nine, luring the children with army rations and small change when their families had nothing to feed them. Some children described to investigators how they were given bottles of water after being raped.